Rotative winged aircraft



July 3, 1945. R. G. ANDERSON ROTA'IIIVE WINGED AIRCRAFT Filed Ndv. 18, 1941 craflgand for. i v i i The type of rotative winged aircraft with which the invention is especially concerned is that in which'the rotor .(or rotors) is normally intended Patented J l 4 h ROTATIVE WINGED' AIRCRAFT ,Robert G. Anderson,Doylestovm,,Pa., assignorto I Autogiro Company of America, Philadelphia;

Bah, a corporation oiDelawai-e h 1 Application November 15, 1941, ScrialNo. 19,5 3

" acl m r (01.244 48) e H l a illustrating the three positions of apthree-way This invention relates to rotative particularly to certain controls thereto beautorotationally ,oraerodynamica'lly rotated in flight, but in which the rotor may be driven winged as l while at rest on the grounddn, preparation for take-off with the rotor blade pitch angle reduced,

so that an initial high R, P, M. may be imparted to the rotor andthe kinetic energy thusstored nection of the rotor'drive. This; general type of may bereleased and converted to lift by increase inventiony Referring first to Figure 1,

control :valve employed, in accordance with the issued October, 1,1940, to J amesG Ray. As shown in said Ray patent, the pitchoithe-blade is controllable by means of an arm 6 with whiclrtli'e take-oflds described more, fully in. copending application oijfJuan dela Cierva; Serial No.

738,349, filed AugustB, 1934, and is also mentioned in copending application of Agnew E. Larsen, Serial No. 363,593, filedloctober 31, 1940, which latter application has issued as Patent No, 2,324,588,

it being noted that said Larsenapplication further discloses certainother features referred to here inaiter, the same being described only briefly herein since they vention per se.

In effecting V theaircraft remain stationary on the ground .during the period or mechanical drive i of the rotor prior to the jump. With tliisin mind we present form no part of thepresent in invention contemplates the employment of-wheel brakes, the operation of which is coordinated with the take-oil controls in amanner providing for automatic application of the wheel brakes when, the controls are adjusted to initiate rotation at the rotor, and for automatic release of thewheel brakes when the controls are adjusted to efiect take-oil. I H r According to the-invention, provision is also made for manual operation otth'e whee1 brakes whenever, desired.

The invention also contemplates othercontrol features, having especial reference to interlocks,

and automatic safety devices whereby the desired type ofjoperationis always assured. v l Various oi the ieaturesot theinvention can best be understood following a description of the control system herein contemplated, to which reierence isnow made, as illustratedin the drawing.

Figure 1 is a schematiclayout of certain parts and devices of the aircraft, with the control sys! tem of this invention appliedtheretoffand Figures 2, 3 and 4 are enlarged sectional views direct take-omit desirable that l cylinder and piston device if cooperates. The control system for device 1 is described below.

the numeral ill;

drive of the tandem airscrews l ibut also for drive of shaft I2 which is extended upwardly to the rotor-hub and connected therewith through gearing andnfdesired, through an oveg clutch so as to ensure free rotation of the rotor in normal a flight.

is actuable by a. brake mediumofanarmtfi; I N The control system of the present invention is: associated with the parts and devices of the aircraft referred'to above; The system includes a source or fluid pressure, such as pump havl The transnussion ill incorporates a rotor drive clutch actuable by an arm l8 so that shaft it y be connected and disconnected withreference to' thepower shaft t. Said transmission ltstillturkth'er provides for drive clutch is connected, and a high speed whenthe rotor drive clutch is disconnected, this being of importance for reasons fully set out in my patent abovementioned. The two speed and the rotor drive clutch are both controllable by a cylinder and piston device it more i dis closed inthe Larsen application above referred to. The controlsystemoi the present invention includes means for supplying actuating fiuidto device it.

Landingwheels for the aircraftare shown at it, each wheel being equipped with a, brake actuablevby an arm 65, movement of which is effected by brake'cylinder ii. A rotor bralre l8 cylinder ts throughthe the root end of a rotor blade is fragmentarily indicated at 5,,itbeh of the airscrews l i. attwo S different speeds, a low speed, when the rotor drive airscrew drive ing a power takeoff at any suitable point in the transmission i3 and deriving fluid (usually oil) from reservoir 22 through the connection 23. The discharge or pressure side of the pump is connected by piping 24 with chamber 26 in the dicated at 26. Line 24 contains a check valve 21 capable of retaining pressure in the control system for a considerable period of time after stoppage of pump 2|, as when the engine 3 is shut off.

The primary control valve 26 has a low pressure chamber 23 which is coupled through pipe 33 with the low pressure reservoir 22. Fluid return to the reservoir may also take place through pipe 31 which interconnects the pressure line 24 and the pressure regulator 32, the

discharge from the regulator being connected with the reservoir through pipe 33. Regulator 32 may be adjustably set to establish any desired normal pressure in the system.

For supplying fluid pressure to the blade pitch control device I, a pipe 34 communicates with Pressure is supplied to the rotor drive clutch 3o device |4 through pipe 43 which interconnects that device and chamber 4| of valve 26.. A

Pipe 44 extends from this valve to thewheel brake master cylinder generally indicated at 46.

r A high pressure line 46 interconnects supply line With the piston 41 of the master cylinder 46 for the wheel brakes in the position shown, the

pressure admitted to the cylinder from pipe 44 is delivered directly to connection 43 havin branches 43a which are coupled with the wheel brake cylinder. |'|.v

Piston 41 of the master cylinder 46 is adapted to, be operated by the pilot through stem 43 which is connected with the center point of rod 63, the ends of this rod being attached to brake operating pedals 6| mounted on the rudder pedals 62. When actuated in this way the pilot may directly control application of the brakes, .it bein noted that the initial movement of the piston 41 closes off communication with the pressure supply line 44. A return spring 53 serves to release the brake pedals.

With respect to the wheel brake and rudder controls and 52, it may be mentioned that link 43 is preferably coupled with rod 63 at a point close to the mounting axis for the rudder pedals 52, so that movement of the rudder pedals will not actuate the wheel brakes. Appropriate universal or other joints may be provided in the wheel brake operating linkage so as to accommodate the various operating movements of the rudder pedals.

, Pressure for operating the rotor brake cylinder i3 is carried through pipe 64 to three-way 1 primary or master control valve generally incontrol valve'55 having an operating handle 56.

From this valve the pressure is conducted through pipe '51 to the device l3. A low pressure or relief line 53 extends from valve 56 to the low 3' sorption movement, a movable part of a shock strut being indicated at,63, a... this movement is employed in the control system to actuate a valve having a control arm 3| which is linked to the movable part of the shock strut as at 62. Valve 63 takes the form of a shut-off valve, the valve being coupled with the pressure line 24 through pipes 63 and 64, and with the relief line 33 (and thus with the reservoir 22) by means of pipes 64 and 63.

Before describing the operation of the control system, the structure of the three-way valves 36,

42 and 66, and also of the primary control valve 23 should be noted.

Each of the three-way valves is constructed as f indicated in Figures 2, 3 and 4, there being a valve memberv proper 66 having a right angle port 36, formed therein. In each of the three mid position interconnects the central pipe connection with the pipe connection at one end of the valve, and movement of the control lever to the other side of the'mid position interconnects the central pipe connection with the pipe connection atthe other end of the valve, as appears in Figures 2 and 4, respectively. 1

i The primary control valve 261s of the piston type, having a stem 61 with an operating knob r 63, the stem can in a valve disc'63 intermediate branch 43a of pipe 43 is connected with threey g way valve 42 having an operating handle. 43.

the aircraft is on the ground with the engine 3 idling, in" preparation for initiating rotation'of the rotor for a-take-oi'f. At this timeall of the valves occupy the positions illustrated in Figure 1. Thus, as to the primary control valve 26, it will be noted that chambers 36 and 4| are both coupled to low pressure through pipe 33. Pressure in the blade pitch control cylinders l' andin the rotor clutch pitch control cylinder |4 isthus relieved. y I When preparing for a take-,offythe rotor pitch control valve 36 is positioned to connect, pipes 34 and 33 and close off communication with the relief line 33. The rotor brake control valve 66 is positioned to interconnect pipes 61 and63, and to close off pressure pipe 64, thereby assuring relief of pressure from rotorbrake cylinder l3. Still further, valve 42 is positionedto interconnect pipes 44 and 43a,and shut off pressure pipe46.

'With'the three-way valves adjusted as men'- tioned (and with the engine 3 iding) the hand knob 63 for the primary control valve 26 is drawn outwardly, the initial effect of this movement being to admit pressure from chamber 25, to chamber 35 which actu'ates blade pitch cylinder 1, thereby reducing the rotor blade pitch angle. Further outward movement of knob 68 admits pressure from chamber 35 to chamber 4| (and blocks intercommunication between chamber 4| and the relief chamber 23) from which pressure is transmitted through pipe 43 to the transmission control unit l4 thereby providing low speed airscrew drive and connecting. the rotor drive clutch. Rotation of the rotor now commences and the rotor is accelerated by opening the engine throttle until the desired take-ofi R. P. M. is attained,preferably an R. P. M. substantially above the normal autorotational R. P. M. of flight.

8 contact with the ground.

a It is to be noted that during this period of rotor drive, pressure is also delivered from pipe 40 through branch 40a and pipe 44 to the master cylinder 45 for the wheel brakes, and thence to the wheel .brake actuating cylinder IT. The wheel brakes are, therefore, retained applied during the rotor acelerating period. i

- When the desired rotor R. P. M. is attained, the

complished by movement oflthe handle 1 56 of valve 55 to its position interconnecting pipes 54 and El and thereafter by movement of the valve toits mid position, so as to retain the pressure admitted to cylinder [9. V

Similarly, pressure maybe admitted to the blade pitch control devices I, by drawing out knob 68 of the main control valve 26 sufllciently to admaster control valve 26 is returned to the position shown in Figure 1, which automatically relieves'the pressure in the blade pitch control device I, the rotor clutch control device I4 and the wheel brake cylinder I 1. As a result of this, the

rotor drive clutch is disconnected and the rotor the ground inthe course of the take-01f may be permitted, when that mode oftake-off is desired. Relief of wheel brake pressure is also desiralbe, having in mindthat upon returnto a landing, the wheels should, of course, be free to rotateupon At the take-off, elongation of the shock struts mounting the wheels results in actuation of valve 68 so as to establish communicationgbetween pipes 68 and 64. I Since these pipesrespectively communicate with the high andlow pressure sides of the system, inadvertent manipulation of the controls in flight will not result in reduction of rotor blade pitch or applicationof the rotor brake or connection of the rotor drive. Upon landing, however, valve 80 is again actuated to disconnect pipes 63 and 64 and thereby condition the entire system for use on the ground in making a subsequent take-off.

The arrangement of the controls for the wheel brakes is of paruticular advantage for several reasons, as follows: In the first place, it should be noted that the control system includes foot operated pedals 5| (in addition to the control valve 42). Handle 43 of valve 42 may be adjusted to admit pressure to thewheel brake cylinders from the supply line 24, and this control may be used when the aircraft is on the ground to apply mit pressure from chamberjfi to pipe34. Upon V introduction of the desired pitch-reducing pres?- sure to devices I, handle 31,0; valve, 38 maybe 1 moved to its mid position-so as to retain the bladesinilow pitch, and therebyavoid undesired development of lift ina wind, when the aircraft is on the ground. Relief of pressure from the cylinders I may :beelfected by adiustingthe valve handle 31 to intercoonnect pipes 38 and 39.

.Fromtthe foregoing it will. be seen that the control system of the present inventionincreases safetyof operation by makingimpossible certain control adjustments which would be undesin able or dangerous, and bysimplifyingthe ma nipulations required by the pilot. Additionally,

, the system is highly flexible, beingcapable of meeting many; diiferent operation conditions. This latter isespecially true with reference to control of the wheel brakes, provisionbeing made not only for automatic wheel brake operation in a manner interrelated with the functions of direct take-oil, but also for two distinct manual operations, one, of which (valve 42) utilizes a power source for application of the brakes and: provides for parking, and the other of which (pedals 5|) is directly operable independently of the power source, so that it may be employed on the ground when the engine andpressure pump are not running. it a I claim:

1. For a rotativewinged aircraft having a var-f iable pitch sustaining rotor capable of effecting direct take-off and having a landing wheel with a wheel brake, a primary pilots control organ for controlling the direct take-oil maneuver, said primary control organ being adjustable between a position providing a non-lifting rotor blade pitch angle and initiation of rotation of the rotor in preparation for directytake-off and a position providing a direct take-off rotor blade pitch setting, mechanism interrelating the op-,

eration of said primary control organ and the wheel brake and providing for application of the wheel brake upon adjustment of the control organ to lower the blade pitch and initiate rothe wheel brakes and also to build up pressure in the wheel brake cylinders ll, which may subsequently be retained by movement of handle 43 to its mid position. Parking at a given point may thereby be assured for a considerable length of time even after the engine 8 (and, therefore, pressure pump 2i) as been shut off.

On the other hand, with handle 43 of the brake' naturally remain filled with oil, so that at any direct take-off and having a landing wheel with a wheel brake, a primary pilots control organ for controlling the direct take-01f maneuver, said time on the ground the pilot may operate the wheel brakes.

Under certain conditions on the ground itmay tation of the rotor prior to take-01f and for release of the wheel brake upon adjustment of the primary control organ to effect direct take-oil,

and separately controllable means for applying the wheel brake independently of theprimary control organ.

2. For a rotative winged aircraft having a variable pitch sustaining rotorcapable of efiecting primary control organ being adjustable between a position providing a non-lifting rotor blade pitch angle and initiation of rotation of the rotor in preparation for direct take-ofi and a position providing a direct take-off rotor blade pitch setting, a source of fluid pressure, a fluid pressure actuating device for the wheel brake, a fluid pressure control system associated with said source and said device incorporating valve meanslproviding for admission of fluid pressure to said device to apply the wheel brake upon adjustment of the pilot's control organ to its position pro-- viding reduced rotor blade pitch angle and 1111-,

tiation of rotation of the rotor before take-on and for release of said'fluid pressure torelease independently of said primary control organ.

3. A construction in accordance with claim 2" wherein the pilot operated control for the wheel fluid pressure. n r 4. Form aircraft a sustaining rotor with a wheel with a wheel brake, afluid actuated device for connecting the rotor drive, a "fluid actuated device for applying the wheel brake,- a source of fluid pressure, and a fluid control system associated with said source and said device and incorporating valve means for admitting pressure fluidfromsaid source to the rotor drive connecting device and for relieving pressure therein, the control system further incorporat ing two independently operable mechanisms for applying and releasing the wheel brake, one of said mechanisms'comprising valve means for adbrake is operative independently oi the source of disconnectible rotor drive and having'a landing valve, and in which the pilot's controlror applying the brake comprises a foot operated pedal.

7; A construction in accordance with claim 4 and further including means automatically op-v erative by landing and take-oi! or the aircraft a to render said control system'efl'ective to apply the wheel brake by ,the pressure' ofsaid source j ,when the aircraftis on the ground and ineil'ec- 1 tive to apply the wheel brake-when the aircraft: is

r 8, .For a rotative a fluid pressure cylinder and piston device ior mitting pressure fluid from said source to the brake applying device and for relieving the pressure therein, the other of said mechanisms comprising a pilot's control providing for development of pressure in said control system by the force exerted by the pilot on said control, so as to apply the wheel brake independently of the pressure available at said source.

5. A construction in accordance with claim 4 in which the valve means for pressure application of the brake comprises a three-way valve one position of which admits pressure from said source to the brake applying device, another position of which disconnects the source but retains said pressure to hold thebrake applied, and the.

third position of which relieves the pressure in said device to release the brakes.

actuating the rotor brake, valve means associated with said source and said device for dellv-.-'

ering pressure fromrsaid source to said .device.

and mechanism operable by-shock absorption movement of "the'landing gear for dispellingpthe brake applying pressure. upon take-off. andreestablishing said pressureupon landing, *withssaid valve means yadjusted qto brake-on -positio'n;

whereby, in preparation for landing. saidvalve means may be adjusted to the brake-kon? position and the brake applying pressure automatically established upon shock absorption move ment of the landing gear incident to landing; f

9. .A construction in accordance with claim 18 wherein said valve means comprises a three-way valve in one positionof. which pressure from said source is delivered to, the brake applying device,. in another position of which said source is cut off but the pressure is retained in the brake applying device, and thethird position 01' which relieves the pressure in said device to release the brake.

ROBERT G. ANDERSON;

r 6; A construction in accordance withclaim-e in which the valve means for pressure applica tion of thebrake comprises a manually'operable' i wing aircraft having a 1-0- tor brake and a landing wheel mounted for shock f absorptionmovement, a sourcerorfluid Pressure, 

